After 主要當介系詞、副詞和連接詞用，而 behind 則主要當介系詞和副詞用。這兩個字的用法可謂「小同大異」，除了有個地方可以互換之外，其他用法皆大異其趣、截然不同。
After 用作介系詞時意為「在 … 之後，在 … 以後；在 … 後面；隨 … 之後」，是指時間的先後順序。例如：
After graduation Allen is going to study abroad. (艾倫畢業後要出國留學)
We’re planning to meet at half after ten. (我們打算十點半見面)
After you, please. (您先請)
After you with the computer, please. (請您用完電腦後給我用)
Mary came in after John. (瑪麗在約翰之後進來)
Paul slammed the door after him. (保羅砰的一聲隨手關上了門)
After 用作副詞時意為「之後，以後」，也是指時間的先後順序。在此用法中，after 通常與其他字構成副詞片語。例如：
Tom got here at ten o’clock and Sam arrived soon after. (湯姆十點到了這裡，隨後不久山姆也到了)
Cindy went on Sunday, and Amy left the day after (= the following day 翌日). (辛蒂是星期天走的，而艾美第二天也離開了)
－ 同樣地，the week/month/year after (= the following week/month/year) 意為「下一週/月/年」。
They lived happily ever after. (他們從此過著幸福快樂的生活)
After 用作連接詞來引導副詞子句時意為「在 … 之後，在 … 以後」。若該副詞子句是指未來時間，則該子句只能使用現在簡單式來表示未來，換言之，該子句不能有表示未來的字詞，如 be going to、shall 或 will。例如：
Soon/shortly after we left, we realized we had forgotten to say thank you. (我們離開不久後就意識到忘了向你道謝)
I went to the library straight/immediately after I left the dormitory. (我離開宿舍後就馬上/立刻上圖書館)
We’ll contact you after we arrive in Seoul. (我們抵達首爾後會跟你聯絡) (正)
We’ll contact you after we are going to arrive in Seoul. (誤)
She’ll move to Taipei after she gets married. (她結婚後將搬到台北) (正)
She’ll move to Taipei after she will get married. (誤)
Behind 用作介系詞時意為「在 … 之後；在 … 後面；隨 … 之後」，是指位置的前後。例如：
Don’t hide behind the door. (別躲在門後)
The professor was standing behind me. (教授站在我背後)
The big temple is located behind the museum. (大廟位在博物館的後面)
Mary came in behind John. (瑪麗在約翰之後進來)
Paul slammed the door behind him. (保羅砰的一聲隨手關上了門)
Behind 用作副詞時意為「在後面；在背後」，也是指位置的前後。例如：
Kevin grabbed his girlfriend from behind. (凱文從背後抓住了他的女友)
Peter drove. His ten-year-old son sat behind. (彼得開車，他的十歲兒子坐在後面)
Nick led, and we all followed along behind. (尼克帶頭，我們全都緊跟其後)
